Outer space has always been used for military purposes. The first rockets were based on the German V-2 ballistic missile, the first astronauts were military personnel, and the first efforts of the two space powers at the time, the US and the USSR, were driven by national prestige and military advantage amid the Cold War. Today, the militarisation of space raises increasingly challenging questions. One of the most pressing concerns is the dual-use classification of space systems and its implications for the laws of war. SpaceX’s Starlink involvement in military operations and active war zones is a particularly timely illustration.

Dual-use space systems

Dual-use technologies can be used simultaneously for civilian or commercial and military purposes, even though they are primarily used in day-to-day civilian and commercial contexts. This classification of space technology as dual-use is legally significant, as it affects whether a system can be considered a legitimate military objective under the laws of war, triggering norms such as the requirement of proportionality.

SpaceX’s Starlink is composed of a vast satellite network that supplies high-speed internet from space to Earth. On paper, it is a fully civilian and commercial service, designed to provide global connectivity everywhere on Earth. At the same time, Starlink constantly challenges this classification. With growing involvement in armed conflicts around the world, such as Ukraine and the Middle East, its dual-use aspects facets are increasingly being exposed.

LUCAS and latest military uses

One recent application of Starlink is the Low-cost Uncrewed Combat Attack System (LUCAS), an uncrewed aerial vehicle designed by reportedly reverse-engineering the Iranian Shahed-136 ‘kamikaze drones’, while adding American-developed systems. Of these, the Positioning, Navigation, and Timing (PNT) system is of particular relevance. This system is designed to use Starlink satellite connectivity to operate in combat environments where GPS signals are disrupted or jammed.

Recently, it has been claimed that LUCAS was used in the operation to capture President Maduro in Venezuela, where the distinctive ‘buzzing sound’ of LUCAS was heard in footage of the attacks. LUCAS has also been widely used in the US Department of War’s Operation Epic Fury, as part of Task Force Scorpion, where it is claimed to use Starlink connectivity to overcome GPS jamming.

Since the beginning of the war in Ukraine, Starlink has supplied internet connection for civilians, as Russian attacks have been aimed at vital infrastructure. More importantly, it has been essential for the Ukrainian Forces, serving as their primary means of military communication. Starlink has also been used for drone operations and more, underlining its vitality for the Ukrainian Forces. All this shows how Starlink is a system that is not only being used commercially for civilian purposes, but also for military purposes, making it a dual-use system.

Legal implications

SpaceX’s growing involvement in modern warfare around the world raises many questions under space law and the laws of war. If Starlink is used in a combat situation, the laws of war apply, including international humanitarian law (IHL). The requirements of legitimate military objectives and proportionality become relevant in this context. According to statements by Ukrainian officials about the dependency on Starlink, it might be seen as a legitimate military objective. Article 52(2) of Additional Protocol I to the Geneva Convention defines this as an object that makes an effective contribution to military action and whose total or partial destruction, capture or neutralisation offers a definite military advantage. The same goes for LUCAS: the neutralisation of its connection to Starlink will harm its PNT efficiency in GPS-deprived combat environments, granting the attacker a clear military advantage.

Even though Starlink can be seen as a legitimate military objective, an attack against it might not fulfill the requirement of proportionality according to Article 51(5)(b) of Additional Protocol I. An attack on Starlink will have widespread effects. It is a commercial service used by customers in more than 150 countries and territories around the world, including remote areas that would lose internet connection and access to essential services. Indeed, an attack on Starlink could have implications beyond the country of origin and cause damage to civilian objects and services that would be excessive in relation to the anticipated concrete and direct military advantage.

Recent developments show that SpaceX might be trying to create some distinction between Starlink’s civilian or commercial and military uses that could solve some of these issues. They are creating Starshield, a system like Starlink, solely for military purposes that shares its characteristics and uses its systems. Starshield is not fully operational yet (with about 200 satellites in orbit, compared to more than 10,000 for Starlink) and still relies on the main Starlink system. Still, it is indisputable that the involvement of space technologies in modern warfare will continue to raise many legal questions.

Space Law, International Humanitarian Law, Law of War, Dual-Use, SpaceX, Starlink